Wheat stripe rust resistance genes Yr5 and Yr7 are allelic

Stripe rust is one of the most destructive diseases of wheat. Breeding for resistance is the most economical and environmentally acceptable means to control stripe rust. Genetic studies on resistance sources are very important. Previous inheritance studies on Triticum aestivum subsp. spelta cv. album and wheat cultivar Lee showed that each possessed a single dominant gene for stripe rust resistance, i.e., Yr5 and Yr7, respectively. Both were located on the long arm of chromosome 2B, but due to the complexities caused by genetic background effects there was no clear evidence on the allelism or linkage status of these genes. Our study, involving an intercross of Avocet S near-isogenic lines possessing the genes, provided clear evidence for allelism or extremely close linkage of Yr5 and Yr7 based on phenotypic and molecular studies.